Liquid metering device

ABSTRACT

The liquid metering device serves to maintain constant the volume of liquid distributed per unit area. The device comprises a quantity regulator driven by a ground engaging wheel for drawing liquid from a reservoir, and supplying it to an outlet via a high pressure pump driven by a power take-off of an auxiliary motor or of the tractor which is used to tow the distributor vehicle. Connected in parallel with the high pressure pump is a regulating return valve controlled by a pressure sensitive device cooperating with the conduit joining the quantity regulator and the high pressure pump. With such an arrangement the delivery through the regulating return valve increases or decreases in response to a decreasing or an increasing respectively in pressure in the conduit which in turn is dependant upon the quantity of liquid actually distributed through said outlet and upon the delivery of the quantity regulator.

United States Patent [1 1 Danquechin Dorval [4 1 Aug. 12, 1975 1 LIQUIDMETERING DEVICE Edmond Danquechin Dorval, 4, avenue des Arts, Versailles(78) Yvelines, France 221 Filed: Feb. 3, 1971 21 App1.No.: 112,261

[76] Inventor:

[30] Foreign Application Priority Data Feb. 16, 1970 France 70.05353[52] US. Cl. 222/177; 137/115; 137/566 [51] Int. Cl. A0lc 23/00 [58}Field of Search 222/71, 72, 177; 137/115,

[56] References Cited UNITED STATES PATENTS 2,965,119 12/1960 Hawkinson137/566 X 2,975.940 3/1961 Nybakke 222/177 FOREIGN PATENTS ORAPPLICATIONS 1,382,919 3/1963 France 111/7 Primary E.\'aminerRobert B.Reeves Assistant Exar'ninerThomas E. Kocovsky Attorney, Agem, orFirmToren, McGeady and Stanger 57 i ABSTRACT The liquid metering deviceserves to maintain constant the volume of liquid distributed per unitarea. The device comprises a quantity regulator driven by a groundengaging wheel for drawing liquid from a reservoir, and supplying it toan outlet via a high pressure pump driven by a power take-off of anauxiliary motor or of the tractor which is used to tow the distributorvehicle. Connected in parallel with the high pressure pump is aregulating return valve controlled by a pressure sensitive devicecooperating with the conduit joining the quantity regulator and the highpressure pump. With such an arrangement the delivery through theregulating return valve increases or decreases in response to adecreasing or an increasing respectively in pressure in the Conduitwhich in turn is dependant upon the quantity of liquid actuallydistributed through said outlet and upon the delivery of the quantityregulator.

7 Claims, 2 Drawing Figures PATENTED 18121975 3,899,106

IN VE TOR= EDMOND Dom AL- lever/z mo A TTOF? N LIQUID METERING DEVICEBACKGROUND TO THE INVENTION The present invention relates to a liquidmetering device and particularly but notsolely concerns the distributionof liquid, especially on the ground for agricultural work.

The distribution of treatment liquids or liquid fertilisers over theground can be effected by the use of pumps working at constant pressure.In the case of variation of the speed of travel, the distributed volumeper unit of area also varies, which may well be harmful; manualadjustment corrections are difficult and inaccurate. Thus it isfrequently preferred to drive a piston pump by a wheel bearing upon theground, which ensures the distribution of a constant volume per unitarea, at variable speed of travel.

However, this simple process does not permit a significant increase ofpressure since beyond a certain absorbed power the wheel skids on theground.

SUMMARY OF THE INVENTION According to the invention there is provided adevice for the controlled metering of liquid from a reservoir comprisinga circuit, including:

a. A first variable delivery pump operating at low pressure adapted todrain liquid from said reservoir and to deliver the quantity of liquidto be distributed,

b. an outlet for said liquid,

c. a second pump operating at high pressure connected between the firstpump and said outlet,

d. a regulating return valve connected in parallel with said secondpump, and

e. a pressure sensitive device connected between the first pump and theparallel connection of the second pump and the regulating valve, saidpressure sensitive device being coupled to regulating return valve tocontrol the latter whereby the return part of the second pump deliverythrough said valve increases or decreases in response to a decreasing oran increasing in pressure in the circuit, said pressure being in turndependant upon the quantity of liquid actually distributed through saidoutlet and upon the delivery of the first pump. In this manner thedevice maintains a low pressure between the first pump and the secondpump in such manner as to avoid on the one hand the absorption ofexcessive power by the first pump, and on the other hand the suction ofthe liquid by the second pump through the first pump.

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a diagramatic layout of a circuitfor controlling metering of liquid in accordance with the presentinvention;

FIG. 2 is a cross-sectional view of an alternative regulator for thearrangement shown in FIG. 1; and

FIG. 3 is a cross-sectional view of another regulator for thearrangement shown in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT In the embodiment shown, a nondriving wheel A bearing upon the ground S drives through a chain orbelt, a disc B pierced with holes .I. In one of these, the eccentricityof which is selected as a function of the desired volume per unit ofarea to be distributed, a pin I of a connecting rod M driving the pistonof a first pump C is passed.

This first pump draws the liquid from a reservoir D through one of twoconduits N and delivers it at low pressure through conduits P towards anair reservoir E then towards a regulator F, having delayed for undelayedaction, and the suction side Q of a pressure pump H operated by a powertake-off represented diagrammatically at I. This power take-ofi' isgenerally that of the tractor which moves the distributor vehicle orthat of an auxiliary motor. It should be noted that as the first pump C,operating as a quantity regulator, works at low pressure, it exerts aweak braking action upon the wheel A, avoiding any skidding. Thedelivery of the pump C is proportional to the angular speed of the wheelA, and therefore to the displacement speed of the vehicle. The choice ofthe appropriate hole J thus permits to the pump C to have at any time adelivery corresponding to that to be distributed, irrespective of thedisplacement speed of the vehicle.

The delivery R leads to distributor elements K represented by way ofexample as a spraying boom.

In parallel with the pump H is mounted a valve G the closure element Gof which is controlled by the regulator F through a connectionrepresented diagrammatically at T. This connection, which is mechanicalfor example, is arranged so that an increase or a decrease of pressure,and therefore of volume, in the circuit of the regulator F causes adecrease or an increase respectively of the return part of the deliveryof the pump H passing through the valve G.

The regulator F can be of any type. As represented it can consist of acylinder the movable piston of which controls the connection T and issubject to the pressure prevailing in the circuit. The regulator F canalso comprise a deformable diaphragm f within a casing F, as shown inFIG. 2, subject to the pressure prevailing in the circuit, or a float f"of an equilibration chamber F", note FIG. 3 following the level of theliquid in the regulator, this level being established as a function ofthe pressure prevailing in the circuit.

The operation of the device is as follows.

At any moment, the first pump C, operating as a quantity regulator,delivers the quantity of liquid which must be distributed, owing to theadjustment of the pin L which cooperates with that of the holes J whichcorresponds to the quantity of liquid to be distributed per unit aera.

If the quantity of liquid actually distributed through the boom K isequal to that chosen, i.e. if it is equal to the delivery of the pump C,the inner operative volume of the regulator F and the pressure in thecircuit remain constant. The return value G remains in its position, dueto the controlling action of the regulator F which is immobile, wherebysaid valve is traversed by the part of the pump H delivery correspondingto the excess of the pump H delivery over the pump C delivery.

This occurs if the wheel A and the pump I-I have each constant speed orif the speed of the wheel A and the delivery of the pump I-I varyproportionally, which is the case for example when the pump H is of thepiston type and is driven by the motor which moves the vehicle.

If the quantity of liquid actually distributed through the boom Kbecomes greater than that initially chosen, i.e. if it becomes greaterthan that delivered by the pump C, the inner operative volume of theregulator F decreases, the part of the pump H delivery returning intothe supplying conduct through the valve G increases, due to thecontrolling action of the regulator F, and the quantity of liquiddistributed by the circuit through the boom K decreases until it isagain equal to the exact delivery of the pump C.

This occurs when the wheel A speed decreases and when, simultaneously,the pump H delivery either remains constant, which is the case when thepump H is driven by an auxiliary motor, or decreases with a quantityless than proportional to the speed variation of the vehicle, or evenincreases, which is the case when the pump H is driven by the vehiclemotor and when the vehicle skids or when the driver uses a shorter ratioin the gearbox.

This also occurs when the wheel A speed increases and when,simultaneously, the pump H delivery increases with a quantity more thanproportional to the speed variation of the vehicle, which can be thecase with centrifugal pumps or roller pumps or occurs when the drivingvehicle skids.

This occurs at last when the wheel A speed remains constant and when,simultaneously, the pump H delivery increases, which is the case if thedriving vehicle skids and/or if the driver uses a shorter ratio in thegearbox.

Conversely, if the quantity of liquid actually distributed through theboom K becomes smaller than that initially chosen, i.e if it becomessmaller than that delivered by the pumps C, the inner operative volumeof the regulator F increases, the part of the pump H delivery returninginto the supplying conduct through the valve G decreases, due to thecontrolling action of the regulator F, and the quantity of liquiddistributed through the boom K increases until it is again equal to theexact delivery of the pump C.

This occurs when the wheel A speed decreases and when, simultaneously,the pump H delivery decreases with a quantity more than proportional tothe speed variation of the vehicle, which can be the case withcentrifugal pumps or roller pump.

This also occurs when the wheel A speed increases and when,simultaneously, the pump H delivery either remains constant, which isthe case with an auxiliary driven motor pump, or increases with aquantity less than proportional to the speed variation of the vehicle,which can be the case with centrifugal or roller pumps, or decreases,which is the case when the driver uses a longer ratio in the gearbox.

This occurs at last when the wheel A speed remains constant and when,simultaneously, the pump H delivery decreases, which is the case whenthe driver uses a longer ratio in the gearbox.

It will be understood that various actions can occur at the same time.They are automatically counterbalanced by the device according to thepresent invention the purpose of which is permit at any moment to thepump H to distribute through the boom K the quantity of liquid deliveredby the pump C.

This device permits therefore to make the delivery through the boom Ksubject to the speed of displacement of the vehicle, irrespective of therotation speed of the pump H and of the eventual skidding of the drivingvehicle, so that the volume of distributed liquid per unit of area isconstant.

The device according to the invention can be utilised in all cases wherethere are variations of relative speed between an atomiser ordistributor nozzle and the surface to be treated, in particular foragricultural sprayers, roller sprayers or sprayers for paper or clothwebs.

What I claim is:

1. A device for the controlled metering of a liquid from a reservoir andfor discharging the liquid onto a surface relative to which the devicemoves, comprising a distributor outlet member for discharging the liquidonto the surface, a flow circuit connecting said reservoir to saiddistributor outlet member, a first metering pump positioned in saidcircuit for withdrawing liquid from said reservoir and for dischargingthe liquid into the circuit downstream of said metering pump, saidmetering pump operating at a first pressure, first driving meansadjustably connected to said metering pump for varying the amount ofliquid discharged by said pump, said first driving means arranged tocooperate with the surface onto which the liquid is discharged andrelative to which the device moves for establishing the delivery rate ofsaid metering pump proportional to the relative speed between the deviceand the surface relative to which it travels, a second pump positionedin said circuit between said first pump and said distributor outletmember, said second pump operating at a second pressure higher than theoperating pressure of said first pump, second driving means for saidsecond pump, said second driving means operated independently of and bya different source from said first driving means, a regulating returnvalve connected to said circuit in par allel with said second pump, anda pressure sensitive device connected to said circuit downstream fromsaid first pump andupstream from the parallel connection of said secondpump and regulating return valve, said pressure sensitive device iscoupled to said regulating return valve for controlling said returnvalve so that the portion of flow through said second pump which passesthrough said return valve increases or decreases in response to adecrease or increase in the pressure in said circuit, the pressure insaid circuit is dependent on the quantity of liquid supplied into saidcircuit from said first pump and the actual quantity of liquiddistributed through said distributor outlet member.

2. A device according to claim 1, wherein said pressure sensitive devicecomprises a movable piston subject to the pressure prevailing in thesaid circuit.

3. A device according to claim 1, wherein said pressure sensitive devicecomprises a diaphragm subject to the pressure prevailing in the saidcircuit.

4. A device according to claim 1, wherein the said pressure sensitivedevice comprises an equilibration chamber and a flot therein whichfollows the level of the liquid in said chamber.

5. A device according to claim 1 wherein the pressure sensitive deviceis connected mechanically to the regulating valve.

6. A device according to claim 1, wherein said first driving means forsaid first pump comprises a nondriving wheel of an agriculturaldistributor vehicle and said second driving means for said second pumpcomprises a power take-off of the motor which moves the vehicle.

7. A device according to claim 1, wherein said first driving means forsaid first pump comprises a nondriving wheel of an agriculturaldistributor vehicle and said second driving means for said second pumpcomprises a power take-off of an auxiliary motor.

1. A device for the controlled metering of a liquid from a reservoir andfor discharging the liquid onto a surface relative to which the devicemoves, comprising a distributor outlet member for discharging the liquidonto the surface, a flow circuit connecting said reservoir to saiddistributor outlet member, a first metering pump positioned in saidcircuit for withdrawing liquid from said reservoir and for dischargingthe liquid into the circuit downstreaM of said metering pump, saidmetering pump operating at a first pressure, first driving meansadjustably connected to said metering pump for varying the amount ofliquid discharged by said pump, said first driving means arranged tocooperate with the surface onto which the liquid is discharged andrelative to which the device moves for establishing the delivery rate ofsaid metering pump proportional to the relative speed between the deviceand the surface relative to which it travels, a second pump positionedin said circuit between said first pump and said distributor outletmember, said second pump operating at a second pressure higher than theoperating pressure of said first pump, second driving means for saidsecond pump, said second driving means operated independently of and bya different source from said first driving means, a regulating returnvalve connected to said circuit in parallel with said second pump, and apressure sensitive device connected to said circuit downstream from saidfirst pump and upstream from the parallel connection of said second pumpand regulating return valve, said pressure sensitive device is coupledto said regulating return valve for controlling said return valve sothat the portion of flow through said second pump which passes throughsaid return valve increases or decreases in response to a decrease orincrease in the pressure in said circuit, the pressure in said circuitis dependent on the quantity of liquid supplied into said circuit fromsaid first pump and the actual quantity of liquid distributed throughsaid distributor outlet member.
 2. A device according to claim 1,wherein said pressure sensitive device comprises a movable pistonsubject to the pressure prevailing in the said circuit.
 3. A deviceaccording to claim 1, wherein said pressure sensitive device comprises adiaphragm subject to the pressure prevailing in the said circuit.
 4. Adevice according to claim 1, wherein the said pressure sensitive devicecomprises an equilibration chamber and a flot therein which follows thelevel of the liquid in said chamber.
 5. A device according to claim 1wherein the pressure sensitive device is connected mechanically to theregulating valve.
 6. A device according to claim 1, wherein said firstdriving means for said first pump comprises a non-driving wheel of anagricultural distributor vehicle and said second driving means for saidsecond pump comprises a power take-off of the motor which moves thevehicle.
 7. A device according to claim 1, wherein said first drivingmeans for said first pump comprises a non-driving wheel of anagricultural distributor vehicle and said second driving means for saidsecond pump comprises a power take-off of an auxiliary motor.